In recent years, a propulsion system including a gas-liquid equilibrium thruster has been developed as a propulsion system for a small satellite. The gas-liquid equilibrium, thruster is a vapor jetting device that jets gas by means of the steam pressure of a propellant, and holds the propellant in the form of liquid in a tank. At the time of posture control, orbit change, and the like, the gas-liquid equilibrium thruster evaporates the propellant, jets only gas from a nozzle, and thus can obtain thrust. The propulsion system including the gas-liquid equilibrium thruster thus configured does not require an air reservoir and a combustor, and hence reduction in weight and size of the system is possible. Meanwhile, improvement of the propulsion system has been desired in terms of how to store the propellant in the form of liquid and how to gasify the propellant in the form of liquid in order to obtain stable thrust (see, for example, Patent Document 1 and Patent Document 2).
For example, in a vapor jetting device described in Patent Document 1, a foamed metal member is provided inside of a tank, and a propellant in the form of liquid is held in air bubbles of the foamed metal member. Then, the vapor jetting device heats the tank to thereby gasify the propellant with the intermediation of the foamed metal member.
Moreover, in a vapor jetting device described in Patent Document 2, a plurality of holding plates are radially placed inside of a tank, and a propellant in the form of liquid is attached to and held by the holding plates by means of surface tension. Then, the vapor jetting device heats the tank to thereby gasify the propellant, and reserves the vaporized gas in a gas reserving space formed in an upper part of the tank.